Democrats have gone on the offensive to push back against the House select committee probe of Benghazi and the failed Arab Spring policy in Libya, but instead they keep reminding us of why it’s needed. For instance, if even a sitting Senator is so ill-informed that she’s pushing arguments that have been long debunked — such as the claim that the consulate in Benghazi couldn’t get security because of Republican budget cuts — then Claire McCaskill is the poster girl for the need for a unitary and comprehensive probe into the attack:

DAVID GREGORY: As you look at Secretary of State Clinton, how she handled some of the questions that have emerged about Benghazi, or even about her health that, as you know, are a question for any candidate, do you think she could have done better? Should she do more to be completely transparent?

SEN. CLAIRE MCCASKILL: Listen, this is a strong, smart leader who is going to be a terrific president. And I don’t care what Reince Priebus says. They do not want Hillary Clinton, because they know she is going to ignite a spark of enthusiasm across this country, and she has got the strongest résumé for president of anyone who’s run in a very long time.

So I really think she’s answered all of the questions about Benghazi. She’s the one who called for an independent investigation. And of course her frustration, when she said it doesn’t matter, was because she wants to make sure this doesn’t happen again. And it was the Republicans that were blocking funding for embassy security. That’s why she was frustrated.

DAVID GREGORY: Senator, you’re an interesting figure politically with regards to the Clintons. Back in 2006, you told my colleague, Jeffrey Goldberg, then in The New Yorker, this: “Hillary Clinton is a sensitive subject for McCaskill. She has told people in Missouri and in Washington that a ticket led by Clinton would be fatal for Democrats on the ballot,” because you didn’t think back then that she could win Missouri.

You came out with two other prominent women at the time to endorse Barack Obama at the same time that Hillary Clinton could have made history back in 2008. And yet now, you were one of the first people to endorse her. What has changed over this arc of time that makes her so formidable in your mind now when she wasn’t before?

SEN. CLAIRE MCCASKILL: Well, I think she was formidable then. It was just a very tough choice. We had two amazing candidates. And it was a difficult primary for our party because they were both so extraordinary. Now she has the experience of secretary of state. I think she has enhanced her résumé. She’s learned so much about how you win these campaigns. She knows how to ignore all the cheap shots and stay focused on the American people and the opportunity that everybody deserves. So I just think it’s her time. And I’m excited to try to be a part of it.

Finally, and most seriously, it is untrue that Republicans blocked funding for embassy security. Here’s Politifact debunking the same myth repeated a few weeks ago on Ronan Farrow’s MSNBC show:

Congress did not fully fund embassy security requests from the Obama administration in recent years, which is what Farrow argues amounts to a “cut.” But funding for embassy security is up from 2008, and up dramatically since before 9/11.

How does this tie into the Benghazi attack? State Department officials and government experts lay more blame on decisions by upper management not to provide the temporary Benghazi facility with more officers and better protections than the availability of money.

Farrow made that very point in his segment, which makes it odd that he led his segment by tying the attack with insufficient congressional funding.

We rate his claim Mostly False.

The testimony from other hearings put this bogus explanation to rest more than a year ago. In fact, the Obama administration itself debunked this claim a month after the attack in Benghazi, as Eli Lake noted at the time. McCaskill’s colleague Barbara Boxer tried using this canard a full year ago, and got roundly criticized for it. Darrell Issa noted at the time that the State Department had been sitting on $2.2 billion in facility funding, which could easily have gone to better security.

If Democrats like McCaskill are still this misinformed more than a year and a half after the attack, it’s incumbent on Congress to produce a comprehensive investigation and conclusion as to how we left a consulate practically undefended in a terrorist-infested failed state on the anniversary of 9/11, and were so unprepared that we couldn’t respond when attacked. Four Americans died in that attack, and their survivors deserve better than the misinformation that some in the political class insist on spreading.